A delay Lcoked Loop Circuit with mixed mode tuning

초록

This paper describes a DLL(Delay Locked Loop) circuit with the mixed-mode phase tuning method. The circuit accomplishes unlimited phase shift and accurate phase alignment through the coarse and fine phase tuning technique. The scheme is based on a dual delay locked loop structure. The main loop is for generating coarsely spaced clocks and the second loop is for the fast and accurate phase tuning with the digital and analog phase detection. Simulations show that this circuit has 360 degree phase shift capability and can resolve 10ps phase error using 0.6mm CMOS technology.